Water soluble thermosetting resin and method of making same



. Patented Mar. 14, 1939 WATER SOLUBLE THERMOSETTING RESIN AND METHOD OFMAKING 8 llamas if. Ne, Aberdeen, Wash.

No Application Au lil, 1937, serial No. 158,4l'it' a car. (oi. ace-sciThis invention relates to water solutions of partial condensationproducts of a methylene condensing agent, such as an aldehyde, and acresol or a xylenol and includes a process of making 4; such solutions.

More specifically this invention relates to the production of cresylicacid-formaldehyde condensation products that are soluble in water andare capable of being set into hard, infusible 10 masses by theapplication of heat.

The water soluble resins of this invention have many uses in the art.They may be used alone or in combination with filling materials forforming pressed or molded articles. They are excellent binders orbonding agents useful in preparin; laminated articles such as plywoodand the like. They also have valuable 'film'forming properties and canbe used in varnishes and other coating or impregnating agents.

This application is a continuation-in-part of my copending applicationentitled: "Method of making plywood, Serial No. 741,745, filed August27, 1934.

Alkaline solutions of phenol-aldehyde resins are known. However, when acresol or a xylenol is used in place of phenol in the formation of analdehyde condensation product, the resulting product is insoluble inWater and will precipitate upon dilution of the reaction mass withwater.

' Therefore, while it is highly desirable to substitute a cheaper cresolsuch as cresylic acid (meta cresol) for the more expensive phenol inpreparing aldehyde condensation products, such substitution hasheretofore not been possible for the production of water soluble resins.

According to this invention cresylic acid, or a xylenol, is reactedexothermically with a methylene condensing agent, such as formaldehydainthe presence of not less than 10% sodium hydrox- 0 ide, or an equivalentamount of other alkali, until a partial condensation product isobtained. Any further reaction is then arrested by the addition of watercontaining 6% sodium hydroxide based on the weight of the cresylic acidor xylenol origi- 45 nally introduced into the reacting mass. Theresulting syrupy solution can be diluted with water in all proportionswithout precipitating the resin. Therefore I am now able to produce anaqueous solution of a cresylic acid-aldehyde 50 resin.

Hydroxy aromatic compounds such as phenol, resorcinol, beta-naphthol,hydroquinone and the like, can be used to replace some of the cresylicacid or xylenol in forming the resins of this in- 55 ventlon. Theseagents combine with any free aldehyde present in the reacting mixture toform additional resinous compounds which serve as hardening agents whenthe product is subjected to heat and pressure for forming an infusible,insoluble "C" stage resin. 5

Small amounts of a gum such as gum accroides can be incorporated in thereaction mixture to increase the bonding qualities of the product.

Small amounts of dispersing agents such as 10 oleic acid andtriethanolamine may be incorporated if desired.

It is then an object of this invention to prepare a stable, aqueoussolution oi a thermo-setting resin.

A further object of this invention is to prepare solutions of methylenecondensation products of cresylic acid or a xylenol that are miscible inwater in all proportions.

A further object of this invention is to pro- 20 vide a stable colloidalsolution of a cresylic acidaldehyde condensation product.

Another object of this invention is to provide a process ofreacting-cresylic acid or a xylenol with an aldehyde in the presence ofa 25 condensing agent to produce a thermo-plastic resin solution that ismiscible in water in all proportions.

A further object of this invention is to control the exothermic reactionbetween cresylic acid 80 and formaldehyde for the production of awatersoluble resin.

Another object of this invention is to react cresylic acid withformaldehyde in the presence of not less than 10% of an alkalicondensing as agent, based on the weight of the cresylic acid, and toarrest the ensuing exothermic reaction with water containing not lessthan 6% alkali metal hydroxide dissolved therein based on the weight ofthe cresylic acid, to produce a solu- 40 tion of a water-solublethermoplastic resin that is miscible in water in all proportions.

Other and further objects of this invention will become apparent fromthe following examples which set forth preferred procedures forpreparing the products of this invention.

Example I 400 parts by weight of cresylic acid are placed in a jacketeddigester together with 432 parts by weight of a 37% to 40% formaldehydesolution. 0.6 part by weight of oleic acid and 1.5 parts by weight oftriethanolamine are introduced into the digester and the ingredients areagitated ,for about one minute to bring about a thorough mixing thereof.The temperature of the mixture is then adjusted so that it will notexceed 62 F.

123 ptirts by weight of a 32.5% aqueous sodium hydroxide solution isprepared and adjusted in temperature not to exceed 60 F. This solutioncontains 40 parts by weight of NaOH which is equivalent to 10% of theweight of the cresylic acid in the digester.

The sodium hydroxide solution is then added to the mixture of chemicalsin the digester and the resulting mass thoroughly agitated. Thisimmediately starts an exothermic reaction, and after one minute thetemperature of the mass rises to about 68 F. This temperature increasesgradually until a somewhat constant temperature of 208 F. is reached inabout thirty-five minutes.

Any further reaction is now arrested by the adtlon of 1000 parts byweight of water containing 24 parts by weight of sodium hydroxide. The24 parts by weight of sodium hydroxide is equivalent to 6% of the weightof the cresylic acid.

After the addition of the 1000 parts of weak alkaline aqueous solution,water is circulated through the jacketed digester to bring the mass downto room temperature.

The product is a syrup having a density between 10 and 12 B., and aviscosity of about 125 centipoises at 87 F. The solid content of thesyrup is between 28 to 30% solids. The syrup has a pH value of about11.4 and can be diluted with water to any amount desired withouteflecting a precipitation of the condensation product.

If less than 10% of sodium hydroxide, or an equivalent amount of otheralkali, based on the weight of the cresylic acid, is used as acondensing agent, a water soluble product will not be obtained.Likewise, if less than 6% of sodium hydroxide, or an equivalent amountof other alkali metal hydroxide, based on the weight of the cresylicacid, is used in the solvent water for arresting the reaction aprecipitation of the resin will result.

The exothermic reaction can be carefully controlled by adjusting theinitial temperatures of the reacting ingredients. The period of reactionmay be considerably reduced in time by adjusting the initialtemperatures of the reacting ingredients to temperatures higher thanthose indicated above but it is then difiicult to arrest the reaction atthe proper point.

The syrupy product obtained can be readily passed through finequantitative filters without leaving a trace of residue on the filters.The syrup shows the tyndal effect and does not precipitate or separateon prolonged standing. These characteristics identify the syrup as anaqueous colloidal solution.

Example I! A modified water-soluble cresylic acid resin can be obtainedby dissolving 10 parts by weight of resorcinol in 400 parts by weight ofcresylic acid and using the same other ingredients in the proportionsindicated in Example I. The same procedure may be followed except thatthe temperature of the initial ingredients may be adjusted to not exceedF. before the aqueous hydroxide solution is added. This hydroxidesolution may be adjusted to a temperature not exceeding 88 F.

The reaction proceeds exothermically after the addition of the hydroxidesolution for about fifteen to sixteen minutes when a somewhat constanttemperature around 221 F. is reached. The

reaction is then arrested by the addition of the solvent water asdescribed in Example I.

The colloidal solution thus obtained has a viscosity of 74 centipoisesat 87 F., and has a density between 10 to 12 B.

Example III In place of the resorcinol in Example 11, 10 parts by weightof hydroquinone may be used, and instead of using the 400 parts ofcresylic acid, 200 parts by weight may be used plus parts of phenol and100 parts of xylenol. The oleic acid may be omitted and 2 parts oftriethanolamine used in place of 1.5 parts, as set forth'in Example I.

The same procedure outlined in Example I is followed but the mass isallowed to reach a temperature of about 214 F. before the reaction isarrested with the solvent water. This temperature of 214 F. is reachedafter about forty minutes.

The colloidal solution or syrup obtained has about the same density asthe solution obtained in Examples I and II, but has a viscosity of 87-90centipoises at 87 F.

Example IV 16 parts of gum accroides may be added to the initialreacting ingredients of Example I. After the sodium hydroxide solutionis .placed in the digester, the reaction is allowed to proceedexothermically until the temperature remains somewhat constant at 204 F.This temperature is reached in about forty minutes.

In incorporating the gum accroides into the reacting ingredients it isdesirable to dissolve the powdered gum in the cresylic acid and strainthe resulting solution to eliminate all particles of gritty matter.

The density .of the solution obtained is between 11 and 12 B., and theviscosity of the solution is 87-90 centipoises at 87 F.

Example V In place of the 400 parts of cresylic acid used in Example I,400 parts of a xylenol, a homologue of cresylic acid, can be used. Thesame procedure outlined in Example I is followed and the same otheringredients are used in the proportions indicated.

The resulting solution has a viscosity centipoises at 87 F.

Example VII In the following example, a modified cresylic acid resin isformed containing phenol.

200 parts by weight,of phenol, 600 parts by weight of cresylic acid, and864 parts by weight of a 37%-40% formaldehyde solution are mixedtogether in a digester. The temperature of the ingredients is adjustednot to exceed 78 F. 246 parts by weight of 32.5% aqueous sodiumhydroxide 'solution is adjusted in temperature not to exceed 72 F. andis introduced into the digester. The ingredients are thoroughly mixed byan agitator and react exothermically for about thirty-five minutes whena temperature around 220 F. is reached. I

The reaction is then checked by the addition of 1000parts by volume ofmethanol containing 48 parts by weight of sodium hydroxide or potassiumhydroxide. This methanol solution may also have dissolved therein 1 partby weight of oleic acid and 2 parts by weight of triethanolamine. I

The resulting syrup is a colloidal solution that may be diluted withwater in all proportions without eifecting a precipitation of the resin.The solution is clear and shows no trace of cloudiness or turbidity.

The methanol used in this example is a substitute for the water used inthe other examples.

Example VIII parts by volume of methanol containing 48 parts by weightof sodium hydroxide. v g The resulting product has a density between 5.6and 9 B.

If desired 600 parts by volume of water and 600 parts by volume ofmethanol may be used in the v checking solution in place of 1200 partsof methanol.

Example IX The following example illustrates how the process of thisinvention can be followed to make a dry, powdered resin that is capableof being redissolved in alcohol or water.

114 parts by weight of phenol, 300 parts by weight of cresylic acid, and432 parts by weight of a 37%-40% formaldehyde solution are mixed toetherin a digester. 123 parts by weight of a 32.5% sodium hydroxide solutionin water are incorporated into the digester. The ingredients reactexothermically upon the incorporation of the sodium hydroxide solutionuntil a temperature around 220 F. is reached. The reaction mixture isthen rapidly cooled untilit is reduced in temperature to 100 F. A gentleheat is ap plied to the mixture to maintain the same at 100 F. until allof the water present is evaporated and the resinous mass is completelyfree from all traces of'moisture.

The dry partial condensation productis then ground in a suitable mill toa fine, pulverized state. The powder may be dissolved in a solventcomprising 500 parts of water by volume, 700

parts of methanol by volume and 24 parts of sodium of potassiumhydroxide by weight. The solvent completely dissolves the powdered resinand a colloidal solution is obtained having a density of about 12 B anda viscosity of about 35' centipoises at 87 F.

If desired a small quantity of a wetting agent can be incorporated intothe product to impart better penetrating properties to the solution.

In the above examples, the initial reacting ingredients have beenadjusted to temperatures around room temperatures, unless a modifiedresin containing phenol is being made, when temperatures above roomtemperatures may be used. It should be understood, however, that theinitial temperatures may be widely varied from room temperatures andthat the temperatures set forth in the examples are used only to permitbetter control of the exothermic reaction. If high initial temperaturesare used, the condensation proceeds with such rapidity that furtherreactions cannot be prevented and an insoluble resin will be produced.The resins of this invention are only partially polymerized and willform highly useful commercial solutions.

The methylene condensing agent, such as formaldehyde, is preferably usedin slight excess over equal molecular proportions with the cresylic Yacid or xylenol to make up for losses due to evaporation and to producea harder resin. However, equal molecular proportions are operative.

The colloidal solutions produced according to this invention can be usedas bonding agents for plywood, as impregnating or sizing agents, as

' binders in the manufacture of fibre board or vegetable fibrousmaterial, and as coating agents.

The solution, when dried, sets under heat to form a film that is highlyresistant to termites, live steam, solvents, acids and alkalies.

I claim as my invention:

1. The method of making aqueous solutions of condensation productsadapted to be diluted with water to any degree without precipitation ofthe condensation products which comprises reacting a cresylic acid witha methylene-containing compound in the presence of an amount of alkalicondensing agent equivalent to not less than 10% of sodium hydroxidebased on the weight of the cresylic acid until a partial condensationproduct is formed and arresting further reaction by incorporating inthe" reaction mass an aqueous solution containing an alkali metaldissolved therein equivalent to not less than 6% sodium hydroxide basedon the weight of the cresylic a'cid.

2. The method of making an aqueous solutionweak, alkalineaqueoussolution containing an' amount of alkali metal hydroxide equivalent tonot less than 6% of sodium hydroxide based on the weight of the cresylicacid.

3. The process of making an aqueous solution of a thermo-setting partialcondensation product of cresylic acid and formaldehyde capable of beingdiluted with water in all proportions without precipitation of theproduct which comprises mixing together cresylic acid and an aqueoussolution of formaldehyde at room temperatures in the presence of notless than 10% of sodium hydroxide based on the weight of the cresylicacid, allowing the mixture to react exothermically for about 35 minutesuntil somewhat constant temperatures around 208 F. are reached andarresting further reaction by dumping into the reaction mass an aqueoussolution of sodium hydroxide containing not less than 6% of sodiumhydroxide based on the weight of the cresylic acid.

4. The method of making an aqueous solution of a thermo-setting partialcondensation product which comprises exothermically reacting a mixtureof a cresylic acid and a different phenol with a methylene-containingcompound in the presence of an amount of an alkali condensing agentequivalent to not less than 10% of sodium hydroxide based on the weightof the cresylic acid and diflerent phenol until a partial condensationproduct is formed and arresting further reaction by incorporating in thereaction mass an aqueous solution containing an alkali dissolved thereinequivalent to not less than 6% sodium hydroxide based on the weight ofthe cresylic acid and different phenol.

29 5. An aqueous solution of a partial condensation product of acresylic acid and a methylenecontaining compound miscible with water inall proportions without precipitation of the condensation product andobtainable by the process of claim 1.

6. An aqueous solution of a cresylic acidformaldehyde condensationproduct miscible with water in all proportions without precipitation ofthe product and having a ratio of alkali condensing agent to cresylicacid equivalent to not less than 16 parts of sodium hydroxide to 100parts of cresylic acid, said product obtainable by the process or claim2.

'7. An aqueous solution 01 a partial condensatlon product of a cresylicacid and a diflerent phenol with a methylene containing compoundmiscible with water in all proportions without precipitation of thecondensation product and obtainable by the process of claim 4. I

JAMES V. NEVIN.

